Rotary hydraulic air compressor



Feb. 13, 1923.

G. MCKERAHAN ROTARY HYDRAULIC AIR COMPRESSOR Filed A'ug, 1921 2sheets-sheet 1 V1 nl m/ l lNvl-:NToR: M971/ Y Feb. 13, 1923.

G. MCKERAHAN -ROTARY HYDRAULIC AIR COMPRESSOR Filed Aug.6, 1921 2sheets-sheet 2 INvENToR:

Patented Feb.. 13, 19273.

f FFIc fr GEORGE NOKENAHAN, or rrr'rsnnnen, PENNSYLVANIA.

ROTARY 'HYDZZR'A'ULIC AIR. COMPRESSOR.

Applicatiniled ug'ust 6, l1921. Serial 130.7490343.

To all 'whom it may concern:

Be it known that I, GEORGE MCKENAHAN, a .citizen of the United States,residing at Pittsburgh, in the county of Allegheny and which theimmediate compressing agent is water to which a. high velocity has beengiven by a mechanically 'rotated'impeller and my objects are to providea compressor of this type which will be competent for high air pressuresand which will utilize more eifectively the energy of the impelledwater. These results are obtained by avoiding the mixing of the waterland air charges and by detaching from the body of the iniiowing watersupply, distinct, separated portions which may be formed into waterpistons of a. shape to lit the air compression tube into which they farehurled, the air charges being delivered to the compression tubealternately with the water pistons. By this method the piston action ofthe water is made more precise and effective and the unobstructed spacebetween the successive water pistons freely admits an adequate aircharge the volume of which can 4be definitely regulated. A furtherobject is to deliver the water supply to the impeller in such manner aswill most effectively utilizeany'initial velocity which the watermaybring from its source. My improvements are especially applicable tothat type of rotary compressor wherein the water pressure from thereceivingl vessel is returned to the impeller. The'- accompanyingdrawings illustrate the mechanism.

Fig. 1 isa vertical view taken on the lines 1-1 of Fig. In this view thenear half of the stationary casing is removed showing the impeller wheeland water supply nozzle in central section; part sections of the aircompression tube and the receiving vessel are also shown.

Fig. 2 shows a generally horizontal section on the lines 2-2 of Fig. 1.

' Fig. 3 is aside view of the impeller wheel removed from its casingboth sides being alike, and Fig. 4 is Aa. section through this wheel onthe line 4 4 of Fig. 3. Identical numbers refer to thesame partsthroughout the several views.

4 A stationary casing l contains'the rotatable impeller wheel' 2 whichhas impeller blades 3 secured to ribs 4l of the wheel hub. Flange pieces5 forming parts of impeller blades 3 serve to connect the latter to ringside plates 6 between which the impeller blades extend. The linterior ofstationary casing 1 is formed into an annular channel `7 which issemi-circular in cross section as shownink F :Ai-g. 2. This channelforms an annular half cylinder concentric with the impeller wheel. Waterpiston formers 8 are fitted between ring side plates 6, of the impellerwheel,to which they are fastened. They are placed immediately in frontof impeller blades 3, in the .direction of rota.- tion, and occupy onlya part of 'the sector between blades, the remaining forward part forminga passage for'the-fair 'charge which is centrifugally fed to aircompression tube y10. The outerfaces of part water piston formers 8 arecircular-half cylinders their a'Xis concentric with the impeller wheeland they are of the same diameter ,as the annular half cylinder 7 of thestationary casingdescribed above. f Thepart piston formers 8 and theannular l half cylinder 7 are complemental to each other having a commonaxis and together they form circular cylinders in which the waterpistons are molded in the manner hereafter described. The front ends ofthesev cylindrical water piston chambers,y in fthe direction ofrotation, are o n while their rear ends are closed. In t e'constructionshown the rear end closure is effected by the 'forward faces of theimpeller blades 3 against which part pistonformers 8 abut in water tightoints.

A convex Senn-circular end of the impeller blade accurately lits andrevolves-.in annular half cylinder 7 ythus completing the rear endclosure o the water piston chamber.

This projecting cylinder end is shown clearly in Fig. 4. v

The sides 9 of casing 1 overlap the rim of the impeller wheel a distancesuicient to prevent water from thepiston chambers being forced out bycentrifugaLpressure.

To reduce leakage the impeller blade ends and the peripheries and sidesof ring side plates 6 will lit casing 1 as closely as may be possiblewithout injurious friction.

A cylindrical air compression tube 10 opensfrom the interior ofcasing 1. This compression tube may have a diameter equal to thediameter of the water piston chambers 'or the tubes diameter may be alittle less ply nozzle 14 may be connected to any original source whichhas sufiicient pressure to feed the water to the impeller, a low speedof the supply flow being compensated for vby increasing the area ofnozzle 14..

But a reduction of the power required to drive the impeller will beobtained if the.

discharge water from receiving vessel 11 is returned to nozzle ltthrougha pipe 13 as shown in the drawings, this water being delivered to theimpeller with considerable velocity as a result of the air pressure invessel 11. When the water is supplied from an original source thepressure discharge Water from vessel 11 may be utilized for otherpurposes. ln this mode of operation the cooling water jacket on vessel11 will not be needed and the effectiveness of the compressors actionwill be in no degree impaired.

lt will be noted that the water is fed circumferentially andtangentially to the periphery of the impelle'r through nozzle 14 in adirect manner which fully utilizes the entering velocity of the water,the air charges being delivered centrifugally through the interior ofthe impeller wheel as already described. A needle 15, internallythreaded supportl, operating Wheel 17, and packing box 18 constitute adevice for regulating the water intake. By varying the water supply thelength and mass of the water pistons may be increased or diminished andflexibility of performance thus obtained for different speeds and airpressures. Where this flexibility is not desired the regulating needle15 and its related parts may be omitted and a fixed size of nozzle usedto suit the requirements. A key ,19 secures the impeller wheel to itsshaft`20- which rotates in bearings 21. Collars 22 fixed to the shaftlimit endwise motion of the latter. The compressor is well suited fordirect motor drive or it may be driven by a belt on pulley 23. Some ofthe water will be absorbed and carried oli' by the compressed air andwhen the water return system is used the watei thus lost from thecircuit will be replaced through pipe 24. Pipes 25 convey thecirculating water for cooling jacket 26 which, in a water return system,will conduct away the heat imparted to the water by the com# pressedair. lPipe 27 leading from the interior of vessel 11 will serve to drainthe lattery when required. Pipes 24,25 and 27 would have suitablevalves.

When the compressed air is delivered from vessel 11 to` al pipe systemof large volume or to a storage receiver an upward opening check valvemay be placed at 28 to prevent a return of the air pressure when thecompressor is temporarily stopped.

ln operation the compressor will .perform as follows; l

The water. delivered through nozzle 14 having a lower velocity than theimpellers a portion of the jet will be cut off by each succeedingimpeller which will leave the jet behind and crowd forward upon thewater in front as shown at A in F ig. 1.

This process in more advanced stage is shown at B. At C the water pistonis fully formed and is then hurled into air compression tube 10 upon theair charge which has already been delivered to the compression tube.'lravel of the air'charge is indicated yby small arrows 29, a part of'the charge having been carried forward in front of the water pistonfrom Afl and B. A water piston D is shown passing through thecompression tube.

lt will be seen how that by feeding the Water supply directly to the'periphery of the impeller Wheel, tangentially thereto and in thedirection of its travel, the higher velocity of the impellers dividesthe water into widely separated masses thus permitting, by centrifugalaction through the impeller wheels interior, of the introduction oflarge bodies of air directly in front of the water pistons, ,the path ofthe air until it reaches the compression tube being entirely free from`any obstruction by the water or otherwise.

For low air pressures and low imvpeller speeds and where a higheiiiciency is not desired the water piston formers 8 may be om1tted ortheir construction simplified.

gli

'It is understood that considerable varia.-

tion may be made in the details of construction without departing frommy invention.

It preferred the water piston forming chambers and air compression tube10 may be made rectangular in cross section instead of circular, theonly requirement being that their cross-sectional areas and outlinesshall respectively conform somewhat closely.

The compressor may be used for other gases besides air.

The relative proportions of air and water charges may be varied eitherby varying -the water supply at nozzle 14 or by changing theI rotationspeed of the impeller wheel.

`What l claim as new is:

1. ln a rotary hydraulic air compressor, a stationary casing; aninterior annular channel in said casing; an impeller wheel within thecasing having like parts of water piston formers spaced around itsperiphery and concentric with the Wheel, these parts of Water pistonformers and the aforesaid annular channel being complemental parts ofcomplete Water piston forming chambers which are inclosed except as totheir `'orward ends in the direction of rotation; a Water inlet throughthe outer circumference of the stationary'casing delivering Water to theinterior annular channel tangentially to the latter and to the path ofthe Water piston formers; air passages through the interior of theimpeller Wheel alternating With the aforesaid part Water piston formers,these air passages reaching to the annular channel of the stationarycasing and leading thence to an air compression tube; an air compressiontube opening tangentially from the said annular channel; a receivingvessel connected to the compression tube; and an air conveying pipe anda water -dischage pipe leading from the receiving vessel.

2. In a rotary hydraulic air compressor, a stationary casing; animpeller Wheel within said casing; a water inlet through the outercircumference of. the stationary casing deliverin Water to the Wheelsperiphery tangential y to the path of the latter and in the directionofits travel; peripheral impellers on said wheel adapted to cut oil',separate and carry forward detached portions of the inlowing Water; airpassages through the interior of the impeller Wheel, said passagesleading to the circular spaces in front of the Water charged impellersand thence to an air compression tube; an air compression tube openingtangentially from the interior of the stationary casing g' a receivingvessel connected to the compression tube; and an air conveying pipe anda Water discharge pipe leading from the receivin vessel.

GEORGE OKERAHAN.

